Pelican Parts Forums - Did Weapons Fail U.S. Troops During Afghanistan Assault?

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Quote:

Originally Posted by m21sniper (Post 4948154)

Very, very, very little of actual infantry firing is directed at specific targets. In vietnam it was something like 300,000rds of small arms ammo fired for every inflicted casualty. Some 85% of all casualties in war are caused by fragments (from mortar/arty/air strikes and grenades).

Not related, but in Viet Nam the sniper was the most round effective weapons system, less than 2 rounds per casualty.
Not quite "One shot, one kill" but close enough compared to the 300,000 round number.
eric

1.6rds per enemy soldier killed.

Quote:

Originally Posted by m21sniper (Post 4950118)

After reviewing the incident I found it encouraging that ours guys seemed to all be firing back. In many past wars the US has had large problems with only a small fraction of the men in each unit actually fighting.

Have you read "On Combat" by Lt.Col. Dave Grossman?
Read that then read "On Killing"
http://www.amazon.com/Killing-Psychological-Cost-Learning-Society/dp/0316330116
http://www.amazon.com/Combat-Psychology-Physiology-Deadly-Conflict/dp/0964920514
eric
Every shooter should read these!

Nope, have not read either. Thanks for the reccomendations.

Quote:

Originally Posted by m21sniper (Post 4950520)

1.6rds per enemy soldier killed.

Cool, didn't know what number came after the decimal point, and didn't wanna make something up! Just knew it was less than 2.0.
eric

The number is quoted in "Marine Sniper."

Snipers and SDM's fill a different role than "regular" riflemen or automatic riflemen. They exist to add an aimed fire precision engagement capability to standard US army infantry units. I don't know if the platoon in question in this thread had any SDM's or not.

Quote:

Originally Posted by m21sniper (Post 4950022)

No offense, but full auto fire sucks dick (the M16A1 was full auto, the 3rd burst of the M-16A2+ is considered an upgrade in the Army's eyes), and an AK will overheat even faster than an AR due to the larger propellant load in each cartridge.

Full auto mode is the real problem....

Quote:

Originally Posted by m21sniper (Post 4950022)

The problem is not exhaust gas blowing into the bolt area, the problem is the actual firing of round after round after round in the chamber in a compressed time frame. This causes the chamber walls to heat to the point of cook-off. As far as i know that has nothing to do with the M-16's direct gas operation system.

The heat issue is unrelated to the operating mechanism to a degree(ha-ha)..Certainly using direct application of combustion gas back onto the mechanism does not assit in cooling the chamber area...

Quote:

Originally Posted by m21sniper (Post 4950022)

The XM-8 was a totally unneccesary "upgrade", that's why it was shelved. In the end it just didn't offer enough(if anything) over the M-4 to warrant such a drastic change and such a large expenditure of $.

That's an interesting view....the H&K 416 was not selected due to that reason... I gained the impression that the XM-8 was not ordered in quantity because of how it came about after the cancellation of the XM29 and its 'single source' procurement route which lead to Colt, among others rightly contesting the procurement.
However it may well be that it did not represent a sufficient step forward to merit quantity procurement despite is demonstrated increased mechanical reliability over the M4. But that is not to say the M4 is not a good weapon, or that the vast majority of troops are happy with it... but its a stretch to say it is therefore the best out there..

We could adopt the greatest latest rifle tommorow, and before it was even fielded in numbers someone would be saying that something else was better.

It's just the nature of the beast i guess.

I have no problem with the XM-8, the HK 416 or the M4. I would take any of them, but if given the choice i would select the M4 over either because i am most intimately familiar with it, and it is is the most combat proven. With the M4 i'd know exactly what i was going to get. The HK 416 has reportedly had problems in Norwegian service, and the XM-8 is really totally unproven. IMO it would be pretty naive to assume it would go into widespread service and not need some significant modifications.

I carried an M-16A1, i thought it was pretty much junk, but the M-16A2 i was issued later was an exquisite weapon. Highly reliable and extremely accurate. The M4 is by all accounts even better.

I have fired a lot of rounds from an AKM, an M-16A1, and an A2.
I don't dislike any of these weapons, but I like them for different reasons.

I have not fired either the AK-74 or the M4.

I agree with you that the long range accuracy of the M-16 cannot be matched by the AK. The 7.62x39 is only good to 400 meters (and that may be a generous number). However the 7.62x39, especially with steel core ammo, has better penetration, anti-armor, and anti-equipment characteristics IMO.

This allows the AK to work well in urban environments where it may be desired to shoot through walls, cars, etc.

Long range accuracy is great to have, but the over 3 million battlefield reports from WWI and WWII were analyzed and the conclusion was that most combat takes place at short range. In a highly mobile war, combat teams ran into each other largely by surprise; and the team with the higher firepower tended to win. The number one predictor of casualties was the total number of bullets fired.

Remember these?

http://bp3.blogger.com/_6B8tPuW7TwQ/...s400/m16a1.jpg

Has the M-4 really advanced much beyond the M-16? Or do you still need a stockpile of CLP to keep them going? If you're not going back to the hotel after each daily patrol, wouldn't you rather have a weapon that is crud-tolerant?

Quote:

Originally Posted by m21sniper (Post 4950663)

I have a copy of "The legend of White Feather", seems Henderson and the publisher "forgot" to give Carlos some cash. The book was published to get Carlos some money and was non profit, to get the maximum cash to Gunny..
Hola
eric

I read marine sniper and the follow up whose title escapes me at the moment. I did not read the one you're referring to though. I'll have to keep an eye out for it. He was a truly remarkable individual.

Quote:

Originally Posted by cashflyer (Post 4950973)

I have fired a lot of rounds from an AKM, an M-16A1, and an A2.
I don't dislike any of these weapons, but I like them for different reasons.

I have not fired either the AK-74 or the M4.

I've fired M-16A1's and A2s in the service both with and without M203s. I am not really a fan of the M203, it ruins the handling characteristics of the M-16 and greatly amplifies the suck factor of humping the thing.

I own a sweetened up Bushmaster XM-15E2S which is essentially a CAR-15, ie a civilain M-4, and i have shot lots of rounds out of many other CAR-15 variants including the Sig 556 and some sweet Colt HBAR models. I have never actually fired an M-4, but i have read a lot of troops comments on them, and the rifle is almost universally loved.

The M-4 has several modifications as opposed to the civilian CAR-15A2 that it evolved from, most notable of which is a different buffer and an improved feed ramp. There are other small detail changes but i couldn't name them off the top of my head. Mine is insanely accurate and reminded me after the first 3rd group i fired from it why i truly loved my M-16A2. Accuracy. The CAR-15 has been around for decades, they are highly refined weapons that work damn well in my opinion. Opinions vary of course, but that's mine.

I fired full auto AKM's in the military, and have fired all kinds of civilian AK's from all kinds of eastern block countries since. They are what they are. By the way, some troops will tell you over on AR-15.com that they've seen AK's jammed in Iraq and A-stan. The weapon has it's merits, but it's just not what i'm looking for in a rifle.

Quote:

Originally Posted by cashflyer (Post 4950973)

I agree with you that the long range accuracy of the M-16 cannot be matched by the AK. The 7.62x39 is only good to 400 meters (and that may be a generous number). However the 7.62x39, especially with steel core ammo, has better penetration, anti-armor, and anti-equipment characteristics IMO.

This allows the AK to work well in urban environments where it may be desired to shoot through walls, cars, etc.

The newer steel core "green tip" M855 round is a much better penetrator at long range than the earlier M193 55gr round was. Inside 50 meters the old M193 actually out penetrates the new round because of it's higher velocity. Either variant will blow right through Class IIIA Armor with ease. It's not exactly a 'bad' penetrating round.

The 7.62x39 round is generally better at tactical penetration but the steel core 139gr military ball round causes a far less severe wound than either M193 or M855, both of which are prone to fragmentation under most conditions.

From the AR-15.com ammo selection section:

Best Choices for Self Defense Ammo

"7.62x39

In discussing 7.62x39 mm FMJ, the question is always which one, as their characteristics are highly variable.

In fact, there is a bit of a controversy brewing in some of the AAR’s coming in from OCONUS on the effectiveness of 7.62 x 39 mm ammunition. Initially, this appears somewhat strange, as there may be more forensic data available regarding wounds caused by the Russian 7.62 x 39 mm FMJ than for any other rifle cartridge. The original 7.62 x 39 mm Russian M43 Type PS 120.5 gr FMJ boat-tail bullet has a copper-plated steel jacket covering a large steel core and a typical muzzle velocity of 2340 f/s. In tissue, it typically travels approximately 9.8 to 10.6" point forward before beginning significant yaw. Most uncomplicated wounds of the torso and extremities have small punctate entrance and exit wounds and exhibit minimal internal tissue disruption since the bullet does not deform or fragment and usually exits before yaw occurs. Total penetration is around 29.1”. WDMET (Wound Data and Munitions Effectiveness Team) collected extensive forensic data on over 700 7.62 x 39 mm gunshot wounds during the Viet Nam war. The predominant feature of this cartridge is the MINIMAL amount of damage it produces in soft tissue wounds, on par with FMJ handgun wounds such as those produced by 9 mm M882 ball. We also have extensive law enforcement data, as this cartridge has been used extensively in illicit activity. For example, in the 17 January 1988 Stockton school shooting, 30 of 35 kids who were shot lived. Of the five that died, all were shot in critical structure--head, heart, spine, aorta and none had damage to any organ not directly hit by a bullet."

------

Civilian high performance expanding ammunition can greatly improve terminal performance, but it comes at the cost of a significant loss of penetration. Conversely, M855 5.56mm wounds much better while still offering performance sufficient to penetrate the US PASGT Kevlar helmet out to 500 meters. An M193 can only penetrate the same helmet to 200 meters, but the light 55gr round almost always fragments and causes a lot of damage.

It's all trade-offs.

And while you may not be able to get through some barriers with a single round of 5.56mm, if you start putting fire on the position most tactical barriers will not remain intact for very long. A 5.56mm SAW can shoot a concrete wall to pieces in very short order. Then again if you are using the right tool for the job your squad's AT-4 gunner will take care of the wall with one shot. Infantry combat is a team 'sport' afterall.

Quote:

Originally Posted by cashflyer (Post 4950973)

Long range accuracy is great to have, but the over 3 million battlefield reports from WWI and WWII were analyzed and the conclusion was that most combat takes place at short range. In a highly mobile war, combat teams ran into each other largely by surprise; and the team with the higher firepower tended to win. The number one predictor of casualties was the total number of bullets fired.

The M-16/M-4 has a higher sustained ROF than the AK-47 and carries a larger ammo load so should be superior in terms of volume of fire.

I do not know what the exact sustained ROF of the AK-74 is but i'd be surprised if it's not comparable to the M-4.

Quote:

Originally Posted by cashflyer (Post 4950973)

Has the M-4 really advanced much beyond the M-16? Or do you still need a stockpile of CLP to keep them going? If you're not going back to the hotel after each daily patrol, wouldn't you rather have a weapon that is crud-tolerant?

I used CLP extremely sparingly in my M-16's. I use graphite powder in my XM-15.

The problem with CLP or any wet oil is that it is a magnet for filth and debris. The only weapons we used a lot of break free on were our M-60s and especially our SAW's. As much to cool them as to lubricate them.

I wonder how many of the soldiers in this battle were smart enough to dump their canteens on their rifle barrels and/or squirt CLP directly into their chambers. That'll cool the old girl down real quick.

Quote:

Originally Posted by HardDrive (Post 4949653)

BS.

After 40 minutes of getting their a55es chewed to pieces, air support arrived and saved their tailsides. Gee, good thing the Taliban don't have fleets of Apaches on call.....

I find this to be a strange opinion. a single platoon of US troops held out against 200+ highly motivated enemy fighters even despite large numbers of their weapons overheating. Are the US forces supposed to apologize for getting air support? Our forces and our equipment are all designed and fielded in appropriate numbers and ratios to operate as part of a well oiled machine.

Certainly if US forces were not designed to operate with air and artillery support they'd be equipped far differently than they are. They are equipped as they are to operate as part of a team effort to deliver victory on the battlefield, no matter the enemies numerical superiority.

That's exactly what they did.

Brave bastages, all of them. It's good to see the American fighting spirit is alive and well. I would venture to guess that a firefight like that is absolutely terrifying to participate in.

I did not mean to disparage the fighting men. They are beyond brave. Heros everyone of them.

Quote:

Originally Posted by m21sniper (Post 4951424)

Agreed on all points of accuracy and flesh penetration.

I have not used the M855 round, so I was unaware of it's tactical penetration ability. I will concede that point to the 5.56 without debate.

I guess my work here is done. lol

Quote:

Originally Posted by jyl (Post 4948493)

I suppose you can't handle a firefight as if you were deer hunting.

But suppose you handled a deer hunt as if you were in a firefight?

Spot possible deer, let 'er loose - suppressive fire, crew-served fire, indirect fire, air support - would it work? What would be the ratio of rounds fired to deer taken?

There is a difference - the deer is not trying to kill you!

No, this is the answer:

http://forums.pelicanparts.com/uploa...1255569863.jpg

When in doubt, ask John Browning. ;)

I don't care who you are, that's funny right there

LOL, i was thinking the same thing. Too bad our guys didn't have circa 1917 water-cooled browning machineguns.

http://www.militaryfactory.com/small...ng-m1917_5.jpg

Something has been bugging me about this, and I just figured out what it was.

Quote:

"My weapon was overheating. I had shot about 12 magazines by this point already and it had only been about a half hour or so into the fight. I couldn’t charge my weapon and put another round in because it was too hot, so I got mad and threw my weapon down.”

12 magazines in a half hour is only 12 rounds per minute. It doesn't seem like that much to me.

In a 3 gun match a few years ago, I put 147 rounds through an AR carbine in 2 minutes (timed stage, 3 rounds left in my 5th magazine when the timer went off). Yeah it got hot (it melted my nylon web sling), but it still ran fine.

I think it's a safe bet that the actual time frame the ammo was fired in was much shorter than the soldier recollected, or was reported.

A well maintained AR will run 500-600rds continuous no problem, but it becomes prone to cook-offs if you leave a round in the chamber after firing all those rounds.

If you reach the point of cookoffs you just lock the bolt back, squirt CLP directly into the chamber until it drips out the other end of the barrel, and douse the exterior of the barrel in canteen water, then you're probably ready to roll again for another couple hundred rounds or so.

M60s and other machine guns are very prone to overheating and can develop "run away gun" syndrome. I saw that on a range at Fort Sill once, it was nuts. The thing just keeps firing until you twist the belt and jam it.

As AR's heat first the handguard becomes to hot to hold, and you grab the magwell. Once the magwell gets too hot you grab the Magazine. Once those are getting uncomfortably hot it's time to cool that bad boy down because you're in serious cook-off territory.

LOL. Dude, you funny.

Quote:

Originally Posted by emcon5 (Post 4953246)

No, this is the answer:

http://forums.pelicanparts.com/uploa...1255569863.jpg

When in doubt, ask John Browning. ;)

Reading the ar15.com thread linked above, there is some good information in there, before the train goes off the tracks completely around page 4. The leaked "rough draft of the historical analysis of the Battle of Wanat, July 13, 2008" is linked, and can be read here:

* Battle of Wanat Historical Analysis: Rough Draft Release*by*A Battlefield Tourist

This is the report the AP reporter used for his hit piece, which shows he was a little hard and loose with facts. The report mentions the M249 barrel getting "white hot", not the M4s, and at least one of the M4 failures (Ayers, RIP) was because it took a bullet through the lower receiver.

Quote:

Specialist Bogar fired approximately six hundred rounds at a cyclic rate of fire from his SAW when that weapon became overheated, and eventually jammed the bolt forward. Specialist Stafford noted, “Bogar was still in our hole firing quite a bit. Then Bogar’s SAW jammed. Basically it just got way overheated, because he opened the feed tray cover and I remember him trying to get it open and it just looked like the bolt had welded itself inside the chamber. His barrel was just white hot.”

On edit, interesting article on The reliability of the M4:
http://www.defensereview.com/m4m4a1-carbine-reliability-issues-why-they-occur-and-why-theyre-our-fault/

That's a seriously detailed report, thanks for posting it.

It really seems as if this one battle was what i suggested some months back in PARF should be our strategy for A-stan, but on a much smaller scale than i envisioned.

Sure sounds as if it was one hell of a fight, even closing to hand to hand ranges at times. I actually walk away from that report thinking those guys were lucky to have thier M-4s and not M-16A1's.

Submitted without comment:
TheFiringLine Forums - View Single Post - M4 Failure makes headlines

Quote:

Originally Posted by a dude on TFL

Bypassing the question of whether or not undermanned units should be trying to carve out miniature Fort Apaches along the Waziristan border...

Some posters seem convinced that M4 combat failure is epedemic due to poor design or, at the very least, somehow contributed to American casualties during two massive and deliberate enemy assaults against small unit outposts.

This thread has been weighing heavily on my mind, as my experience with the same weapon over the last few decades (and several combat tours) does not correlate with that of a number of posters who claim the M4 is liable to fail under stress.

That said, and because I'm currently employed in an organization that issues M4A1s and likes to see them used...

Today I conducted an impromptu and completely unscientific test of my weapon in order to see if I had merely imagined my faith in the little beast.

With this thread fresh in my mind, I broke out 10 brand new GI issue, aluminum body, green follower, Center Industries 5.56 magazines and proceeded to load them with 30 rds each. Not 26, 27, or 28...30 rounds each.

I then proceeded to successfully fire 1140 rds (38 magazines) of M855 62 grain "Greentip" 5.56 through my well used M4A1, on full auto, and in well under 30 minutes.

I checked my watch, noting start time, and began firing the first 10 mags in 3-5 round bursts at a 5 meter target, from a standing position, and executing medium speed combat reloads as each mag ran dry. Shoot to bolt lockback, drop mag, insert new mag, resume fire. 10 times...300 rounds in about 3 minutes.

I then let the rifle cool for about 8 minutes while I reloaded all 10 mags.

Rinse. Repeat. 10 mags in about 3 minutes.

Gun cooled for exactly five minutes while I reloaded all 10 mags at a slightly faster pace.

Rinse. Repeat. 10 mags again in under 3 minutes with slightly longer bursts of 7-9 rds each. By this time, I had lowered the weapon to "hip fire" (just in case...rather have a cookoff or malfunction away from my face).

Last iteration. Let carbine cool while I loaded 8 mags in under 5 minutes. I didn't have a new case of ammo open and I didn't want to slow down the proceedings. Fired all 8 from the hip as fast as I could reload (in about 1 minute and 30 seconds, full auto, trigger depressed until magazines were empty. No attempt at burst fire.

38 x 30-rd magazines fired without a stutter,...in under 28.5 minutes, without a jam, misfeed, doublefeed, cookoff or failure to completely chamber, extract or eject. It hummed like a sewing machine, put all rds on target (except for a few flyers from the hip), and never changed a beat with regards to getting sluggish from fouling.

This performance was delivered by a stock military issue M4A1 that has seen 10s of thousands of rounds down the barrel, probably 5 combat deployments, several months worth of PMT (Pre Mission Training for combat deployments), several shooting schools, and many months of team ranges at home and abroad.

My carbine was relatively clean and I oiled it prior to firing as I stood on the range. I shotgunned the upper receiver, dripped some CLP on the trigger group, liberally coated the charging handle, chamber, and bolt carrier group (without disassembling the bolt from the bolt carrier) and slapped it back together. Aimpoint M68 "on", nomex clad hands on pistol grip and vertical foregrip, KAC quad-rail run exposed with no rail covers (don't need 'em or like 'em).

1140 rounds. Thats three times as much ammo as a normal infantryman would be likely to ever carry on his body, thirty-eight magazines, more than five basic combat loads...all on full auto...in well under thirty minutes. Nemo Problemo.

The upper receiver was still a bit too hot to touch (rear rail, barrel, and ejection port area) without gloves after 10 minutes, but the lower receiver was good to go barehanded.

I took an assumed risk (induced weapon failure) and wore adequate protective gear, but (as it turned out), nothing was necessary. Didn't even need gloves as the vertical foregrip stayed cool.

Someone will no doubt question my ability to conduct such a "test" on a military range. I'll simply say that I have enough rank that very few folks question what I do or why I want to do it.

It's not the first time I've put a lot of rounds down an M4A1, but it's the highest round count I've shot recently in such a short period of time.

Of course, this just an anecdotal account of my experience with just one weapon, but my faith in the M4A1 remains affirmed.

BTW: My barrel didn't get white hot...just black with wisps of smoke coming off of it.

YMMV.
__________________
Figure The Odds...

So if I read that correctly, if you maintain this weapon, it is practically foolproof; we have failed to adequately define PMS/maintenance hence failures

Quote:

Originally Posted by m21sniper (Post 4950093)

The USMC wants to replace some M-16A4's with some new fangled squad automatic rifle that will automatically switch to open bolt operation when it heats up, so that they can increase the volume of fire of their units.

I like this idea. Seems like for a squad gun, you could do the do the cooling fins like on an air cooled car, water is too heavy to tote, though I bet it you could devise a method to take advantage of it as a medium for cooling for a fixed position.

How long could you shoot the bad to the bone MG '42 the Germans had before it would overheat? I know they had a pretty impressive rate of fire, but you burn that much energy you create a lot of heat, gotta go somewhere.

Quote:

Originally Posted by Tobra (Post 4955560)

How long could you shoot the bad to the bone MG '42 the Germans had before it would overheat? I know they had a pretty impressive rate of fire, but you burn that much energy you create a lot of heat, gotta go somewhere.

MG42 has quick change barrels. Throw a lever, pull the barrel out and pop in a cool one.

Fast forward to about 1:55, you can see how it comes out:
YouTube - German Machine Gun MG42

Quote:

Originally Posted by Tobra (Post 4955560)

Quote:

Originally Posted by m21sniper

FNH IAR?

IAR

The problem with open bolt weapons as battlefield systems is that in harsh environments they are prone to eat a lot of dust, dirt and debris.

The US military could certainly put full length fluted and thermally coated barrels on pretty much everything, but it would cost a lot of money.

I'm personally not really worried about it, even if i fire off every round from every magazine i own including my Beta C double drum it's still only 600rds.

More on M855 armor penetration capabilities:

"Q. Isn't 7.62 NATO much better for long range penetration than 5.56 anyhow? Why would I want to use 5.56 when I could send 7.62 downrange instead?

Well, yes and no. For some penetration mediums like mild steel, M855 is actually superior. Consider a recent research report:

The SS-109 can penetrate the 3.45mm standard NATO steel plate to 640 meters, while the 7.62mm ball can only penetrate it to 620 meters. The U. S. steel helmet penetration results are even more impressive as the SS-109 can penetrate it up to 1,300 meters, while the 7.62mm ball cannot penetrate it beyond 800 meters.

The current production 7.62×51mm NATO ball cartridge has remained unchanged since its adoption by NATO in 1953. As typified by the U. S. M80 ball and the Belgian M77 ball, this cartridge propels a 147-grain cupronickel-jacketed lead bullet at a muzzle velocity of 2,800 fps (848 mps). Total cartridge length and weight are 2.80 inches and 386 grains, respectively. Utilizing a standard 22-inch barrel with a rifling twist of one turn in twelve inches (M14 rifle), the maximum effective range of the 7.62×51mm ball cartridge is listed as 620 meters (682 yards). The U. S. M80 and the Belgian M77 ball projectiles can penetrate the standard NATO 3.45 mm (.14 inch) thick steel plate up to a range of 620 meters and can penetrate one side of the U. S. steel helmet up to a range of 800 meters (880 yards). In barrier and fortification penetration tests, the 147 grain ball projectile can consistently penetrate two test building blocks.

The new SS-109 cartridge propels a heavier 62-grain semi-armor piercing projectile at an initial velocity of 3,050 fps (924 mps). The improved projectile contains a 10-grain .182 caliber hardened steel penetrator that ensures penetration at longer ranges.

The new projectile can penetrate the standard NATO 3.45mm steel plate up to a range of 640 meters (704 yards) and one side of the U. S. steel helmet up to a range of 1,300 meters (1430 yards). In tests of barrier and fortification penetration however, the steel penetrator of the SS-109 could not pierce any of the test building blocks.

The primary advantages of the intermediate power 5.56×45mm NATO cartridge are summarized as follows: (1) the penetration and power of the SS-109 version are superior to the 7.62mm NATO and more than adequate for the 300-meter average combat range documented in actual battle (ORO studies): (2) the lower recoil generated by the 5.56mm cartridge allows more control during full automatic fire and therefore provides greater firepower to the individual soldier; (3) the lesser weight of the 5.56mm ammunition allows the individual soldier to carry more ammunition and other equipment; (4) the smaller size of the 5.56mm ammunition allows the use of smaller, lighter and more compact rifles and squad automatic weapons and; (5) the lethality of the 5.56mm projectile is greater than the 7.62mm projectile at normal combat ranges, due to the tendency of the lighter projectile to tumble or shatter on impact. 5.56-mm NATO ammunition weighs only 47% as much as 7.62 mm NATO ammunition.

In summary, the 5.56mm NATO provides greater firepower and effectiveness than the larger and heavier 7.62mm NATO."

The AR15.com Ammo Oracle

Here's a link to the pelican thread on 5.56mm ammo selection:
http://forums.pelicanparts.com/off-topic-discussions/496791-what-your-choice-5-56mm-ammo.html

I also found this on the ammo oracle link:

"M193 and M855 at anything greater than 2200 fps will generally defeat all body armor up to and including Type IIIA. How much damage those rounds will do AFTER penetration is guesswork. In shorter barrels (14.5" and below) that damage is likely to be limited and wound profiles in such instances will resemble .22LR hits. With higher velocities it's still hard to imagine explosive fragmentation at anything but point blank range but M193 and M855 will certainly defeat all soft armor."

It seems to me the newer heavier 77gr US Military bullets would still retain sufficient velocity to fragment (2100fps floor) even after penetrating class IIIA armor.

I just fired 204rds of full power .223/5.56mm through my AR Carbine in about 3 to 4 minutes yesterday, trying to see if i could get the rifle to malfunction.

The first part of the test was a standard silhouette target at 25 yards. The second target was a standard silhouette at 7yards.

I started with with aimed fire, shooting 13rds of heavywieght max. pressure Double Tap 77gr JHPBT's to get the barrel warm and fine tune my zero. I then reloaded the weapon and went into "mad minute mode", firing a 100rd beta C double drum mag of American Eagle 50gr Federal JHP as fast as i could while keeping the front sight post centered on the target.

I quickly followed that up with 3x 30rd mags of the same Federal JHP ammo rapid fired and reloaded as fast as possible, again while recentering my front sight on the target between shots- one mag right after the other.

No failures of any kind occured.

The standard US combat loadout of 5.56mm is 210rds of M855 in 7x30rd mags. My test yesterday closely approxomated what would happen if a US soldier had to rapid fire his entire combat loadout in a matter of just a few minutes.

After firing the 204rds the weapon was pouring smoke from the action, muzzle and free floated handguard tube end, but the Hogue overmolded rubber portion of the handguard was only slightly warm.

Temperature inside the range was about 60 degrees F.

I should have video of the Beta-C mag portion of the test in a day or two, once my buddy uploads it.